Comfort tyres are actually pretty good in the rain. If you want to try aquaplaning, get Sport or Racing slicks.
The right kink after Eau Rouge at Spa is notorious for having puddles in the rain (at least in ACC, it always does). That would be the first place I'd test for aquaplaning. It's at high speed so you won't confuse aquaplaning for usual wheelspin. If your car doesn't slide across the track then aquaplaning isn't simulated.
I'm the opposite. PD is 1 or 2 generations behind on current cars (as they always do).
No Alfa Giulia.
No New Vantage/DBS SL/Valkyrie.
No New M4 (or M2/M5/M6/M8 for that matter).
No Chiron.
No C8 Corvette.
No SF90 Stradale or 812 Superfast.
No i20N or i30N.
No Centenario or Sian.
No MC12.
No 600LT/720S/Senna/Speedtail/Artura.
No AMG One.
No 918 Spyder (despite having LaFerrari and P1 GTR) or 992 GT3.
No New BRZ (literally just a bumper change on the GR86).
No New Teslas.
No Mk8 Golf GTI/R.
And still missing critical brands like Bentley, Lotus, Koenigsegg, Caterham, Volvo/Polestar, Kia, Holden/FPV...
I love old cars but PD has never been up to date with new cars (except Japanese brands) and it's the same with GT7.